Dockerfile instructions, layer caching, multi-stage builds, docker compose, bridge and overlay networks, volumes and registries.
41 cards · basic cards · AI-written, checked twice. Edit anything.
- What does the FROM instruction do in a Dockerfile?
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Specifies the base image from which the new image inherits- What instruction changes the working directory inside a Dockerfile?
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WORKDIR- What does RUN do in a Dockerfile?
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Executes a command inside the image during the build process- What instruction copies files from the build context into the image?
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COPY- What is the difference between COPY and ADD?
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ADD can download remote files and auto-extract archives; COPY is simpler and preferred for local files- What does EXPOSE do?
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Documents which ports the container listens on, but does not actually publish them- What is the difference between CMD and ENTRYPOINT?
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ENTRYPOINT specifies the main executable; CMD provides default arguments that can be overridden at runtime- What does the USER instruction do?
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Sets the user that runs all subsequent commands and the container itself- What instruction declares a health check for a container?
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HEALTHCHECK- What does the ARG instruction do?
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Defines a build-time variable that can be passed with --build-arg and is not available at runtime- Why should frequently-changed instructions be placed later in a Dockerfile?
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To preserve the cache of earlier, stable layers and speed up rebuilds- What happens when a layer's cache is invalidated?
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All subsequent layers are rebuilt, even if their commands have not changed- What does the --no-cache flag do when building an image?
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Forces a complete rebuild, skipping all cached layers- How does Docker determine if a cached layer is still valid?
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By comparing checksums of the layer's commands and the contents of any source files copied into it- What keyword enables multi-stage builds in a Dockerfile?
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FROM with an AS clause, used multiple times in the same file
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